The first chapter is a meta-analysis of studies which compare the hippocampal volumes of individuals with a history of mild traumatic brain injury (mTBI) to healthy controls. The results showed that individuals with mTBI have reduced left and right hippocampal volumes compared to control participants. The second chapter is an empirical paper comparing virtual reality route learning performance and hippocampal volumes of individuals with mTBI to a control group. The data collection was disrupted by Covid-19, and therefore it is presented as a pilot study examining the suitability of the methodology. The results showed that there were no significant differences in route learning performance, and the volumetric analyses revealed that individuals with mTBI had significantly larger left and right hippocampal volumes compared to the control group. Recommendations for future research are related to the inclusion criteria for mTBI, and controlling for confounding variables which may influence hippocampal volume, specifically psychiatric disorders and sports participation/aerobic fitness levels. The third chapter contains two press releases summarising the results from the first two chapters.